The invention relates to an equipment by the aid of which alphanumerical and/or pictorial information can be displayed even under unfavorable working conditions. The invention can preferably be used on a vehicle or such other establishment where disturbing factors causing instability may arise, however the working features of the display equipment should not be allowed to be disturbed by such adverse conditions. It is a special advantage of the invention that many embodiments based on some common main features but differing otherwise considerably from each other may be built so that any special requirement can be complied with: the embodiment may be a manually operated primitive display device as well as a sophisticated equipment having large dimensions and many features, among others, the possibility of automatically changing the displayed pattern according to a time-table. It is a common structural feature of all embodiments that the essential operating, actuating devices according to the invention are uniform modular elements which may be arranged in any desired number and combination and this is very favorable especially as far as the possibility of wholesale manufacture, the interchangeability of components, and the universality of operating conditions are concerned.
Various solutions have been developed for displaying alphanumerical and/or pictorial information and they may be assorted according to different criteria. A widespread group of means for displaying both alphanumerical and pictorial information includes equipment comprising a matrix-type display board. This group may further be broken down if one considers whether the dots formed in the nodes of the matrix are of the so-called active or the so-called passive type. Active dots are, e.g., those formed by a light source (incandescent lamp, cold light source, light-emitting semi-conductor, ett.). Such dots are during the whole displaying period continuously emitting light energy causing thereby an either smaller or greater but a continuous energy consumption. The use of so-called passive dots allows the reduction of energy consumption which may in this case often be restricted to the energy needs of the control means; sometimes there arises also a minor energy consumption for turning a dot into and, if necessary, positively holding it in its actuated state. One of the known passive dot type display boards is comprising a plate the surface of which is painted in a certain color (hereinafter: ground-color) and carries a plurality of annular dots forming the nodes of a matrix. The dots are prepared by leaving a semi-circle of the dot ground-color painted and painting the other semi-circle in a different color, and a semi-circular cover plate painted on its one side in the ground-color and on its other side in the different color is arranged at each dot in a manner that it can be rotated around the median line of the dot by 180.degree. in order to cover the one working position the ground-color painted semi-circle of the plate and, thus, show an annular dot of the different color, whereas in the other working position the differently colored semi-circle of the plate is covered and the dot is, thus, shading into the ground-colored surface of the plate.
The matrix-type equipment comprising active or passive dots according to the prior art requires either a skilled personnel or an automatic--usually electronic--control unit leaving only simple manipulations to the operating layman. The known equipment are all more or less susceptible to the instability factors prevailing in the working area. With vehicles, the main instability factors are the considerable shaking effects; frequent deviations from the horizontal position to a widely varying extent; vibrations due to changes in speed; an enormous contamination; considerable changes in the ambient conditions, such as, temperature and precipitation exerting a direct influence on the working area. In this field of application, a robust operating mechanism is necessary. Since the operation shall usually be performed by laymen, a solution is sought for which does require no cyclical maintenance and, qualitatively as well as quantitative, a minimum interference on the side of the operator. The solution should afford an easy manipulation for laymen without the need of expensive automatic control devices but with the possibility of improving the basic mechanism, if needed, with a versatile and high-capacity automatic control means.